Colon polyps and cancer.

The superiority of colonoscopy to double-contrast barium enema in detecting neoplasia was finally demonstrated in 2000, but colonoscopic surveillance programs are still based on short-term observations and are mostly inadequate, despite the prospective design of the trials. The evaluation of the diagnostic accuracy of virtual colonoscopy is in progress, but its appropriate place in clinical gastroenterology has not yet been defined. There is now solid evidence that screening with fecal occult blood testing (FOBT) not only reduces the mortality from colorectal cancer, but also that the incidence is substantially reduced after removal of the precursor lesions. Feasibility studies for population screening are ongoing. A once-only sigmoidoscopy will probably not be an optimal method of screening, but may be added to a program with FOBT. Molecular stool screening is attractive, but still experimental. Colonoscopy is not attractive as an initial screening instrument, despite its high diagnostic accuracy, and should only be used for screening high-risk individuals. Genetic methods are playing an increasing role in defining prognostic markers for intestinal neoplasia, and it is recommended that information services should be established for the public. Chemopreventive studies have revealed that dietary fiber supplementation may not reduce the risk of adenomas; the opposite seems to be true for aspirin and non-aspirin NSAIDs, which are active in the early phase of carcinogenesis. New techniques for optimizing diagnostic and therapeutic colonoscopy have been introduced.